Laccase is a polyphenol oxidase (EC 1.10.3.2) which catalyses the oxidation of a variety of inorganic and aromatic compounds, particularly phenols, with the concomitant reduction of molecular oxygen to water.
Laccase belongs to a family of blue copper-containing oxidases which includes ascorbate oxidase and the mammalian plasma protein ceruloplasmin. All these enzymes are multi-copper-containing proteins.
Because laccases are able to catalyze the oxidation of a variety of inorganic and aromatic compounds, laccases have been suggested in many potential industrial applications such as lignin modification, paper strengthening, dye transfer inhibition in detergents, phenol polymerization, hair colouring, and waste water treatment.
No three-dimensional structural information has been available for a laccase before.
We have now elucidated the three-dimensional structure of a Coprinus cinereus laccase. By having this three-dimensional structure we are able to create laccase variants with altered properties: increased oxidation potential and/or changed pH optimum and/or altered mediator pathway and/or altered O.sub.2 /OH.sup.- -pathway.